[1.14.3] Check VillagerEntity attributes before opening trade screen

[eafooe]

Hello,

I am trying to prevent a player from opening the trade screen with a villager if they have previously removed the villager's nose with a pair of shears. The trade screen should never open, and the player should be told "Leave me alone! I miss my nose". 

 

I have stored whether the villager has a nose by attaching a capability to all instances of VillagerEntity. But I am having difficulty obtaining the VillagerEntity instance before I open the trade screen. I tried casting the IMerchant from the MerchantContainer to an AbstractVillagerEntity (which implements IMerchant) as well as VillagerEntity, but all I get are ClassCastExceptions. I must be overlooking something.

 

This is what I have so far (throws ClassCastException):

    @SubscribeEvent
    public static void guiOpenEvent(GuiScreenEvent event){
        if (event.getGui() instanceof MerchantScreen){
            IMerchant merchant = ObfuscationReflectionHelper.getPrivateValue(MerchantContainer.class, ((MerchantScreen) event.getGui()).getContainer(), "merchant");
            if (merchant instanceof VillagerEntity){
                VillagerEntity villager = (VillagerEntity) merchant;
                INose noseCapability = villager.getCapability(NOSE_CAP).orElseThrow(() -> new RuntimeException("No inventory!"));
                if (!noseCapability.getHasNose()){
                    event.setCanceled(true);
                    event.getGui().getMinecraft().player.sendChatMessage(String.valueOf(new TranslationTextComponent("translation.villagersnose.trade_refusal", (Object) null)));
                }
            }
        }
    }

 

How can I determine which VillagerEntity instance the player is attempting to trade with?

Edited August 9, 2019 by eafooe
clarification

[eafooe]

Bump.